The present invention relates to cost modeling of communication networks. More specifically, the present invention relates to determining cost structures for radioport architectures.
Wireless, or cellular, communications networks are based on the concept of dividing a radio coverage area into units called cells, each of which contains a radio access port, or radioport (receiver/transmitter/antenna combination) that communicates with wireless users within the cell. As users move across the terrain, they move from one cell to another. Their calls are handed off from the cell they are leaving to the cell they are entering, ideally without any noticeable effect. By dividing the service area in this manner, it is possible to reuse the frequencies allocated from cellular telephony many times, thereby increasing the efficient use of the allocated spectrum.
Wireless communications is a capital-intensive business, and carriers are continuously seeking to reduce costs associated with cellular communications networks. The total system infrastructure cost of a cellular communications network fixed plant can be decomposed into three major elements: switching, interconnect, and radio access. As such, a total system infrastructure cost may be written as:
Ctot=Csw+Cin+Cradxe2x80x83xe2x80x83(1)
where Ctot=total system infrastructure cost, Csw=total switching and control segment cost Mobile Switching Center/Base Station Controller (MSC/BSC), Cin=total cost of interconnecting control and radio segments, and Crad=total radioport segment cost. Each cost component is a sum of its elemental costs, such as equipment, land, and facilities.
Conventional cellular radio access equipment is large and expensive. Land and buildings required to contain the conventional cellular radio access equipment are similarly large and expensive. Therefore, the radioport segment cost, Crad, has traditionally been the largest cost element in cellular systems.
A trend in wireless communications is towards lower-power, more closely spaced radioports, also known as base stations, access points, and base station transceivers. As radioports become smaller, they also become less costly. In particular, smaller, lighter radioports can be mounted on utility poles or the corners of buildings rather than requiring dedicated sites, buildings, and towers. This trend should reduce the real estate costs associated with the larger dedicated sites, buildings, and towers. A reduction in real estate costs consequently results in a reduction of the radioport segment cost, Crad.
Many established and developing cellular markets have dense user populations. There are two ways to serve more users within a cellular or microcellular system, the traffic-handling capacity of each cell is increased or more spectrum is used. The traffic-handling capacity improvements are being achieved using advanced technologies such as code division multiple access (CDMA), but these are insufficient, in and of themselves, to provide the additional needed capacity.
Since the absolute amount of spectrum available for a cellular system is fixed and inelastic, additional spectrum can be gained only through reuse, which means closer spacing of cells than is customary in traditional cellular systems. Indeed coverage radii for a personal communications system (PCS) or another microcellular cell is approximately equal to or less than three kilometers. Accordingly, the smaller, more closely spaced, radioports are particularly useful for serving more users in regions of dense user concentrations. Although more of the smaller radioports are needed, their unit costs will drop such that the share of total costs represented by the radioport segment cost, Crad, will drop.
Owing to the considerable investment required in a wireless communications network, models have been developed to attempt to optimize the costs of wireless networks. Wireless communications networks are complex systems, and the development of an optimal cost solution for the interconnections of such a complex network is a difficult problem in combinatorial mathematics. However, the problem of designing optimal cost networks has received much study because it is important to the design of networks that they can return a profit to their operators.
In general, these problems do not possess analytical solutions and are typically attacked using various heuristic methodologies. In turn, these heuristic methodologies are mathematically complex and require significant computational power and time. Due to their complexity and cost, the heuristic methodologies are avoided by practicing network designers. In addition, some of the methodologies, are only useful over a small set of reasonable conditions. Yet another problem with prior art techniques is that many of these methodologies are designed to be used only after the radioports have been specified and designed.
For the reasons discussed above, many prior art network cost optimization methodologies are not commonly used in the practical design of wireless network infrastructures, which virtually ensures non-optimal topologies.
Accordingly, it is an advantage of the present invention that a method is provided for determining system architecture for radioports in a wireless communications network.
It is another advantage of the present invention that the method identifies a cost optimal system architecture for the radioports.
It is another advantage of the present invention that a cost optimal system architecture is identified that is suited for a dense user topology.
The above and other advantages of the present invention are carried out in one form by a method for selecting one of a plurality of radioport architectures of radioports in a wireless communication network. The method calls for specifying parameters associated with the radioports, and computing composite powers for the radioport architectures in response to the parameters. Cost structures are determined in response to the composite powers for the radioport architectures, and the cost structures of the radioport architectures are compared to select the one radioport architecture.
The above and other advantages of the present invention are carried out in another form by a computer-readable storage medium containing executable code for instructing a processor to select one of a plurality of radioport architectures of radioports in a wireless communication network. The executable code instructs the processor to perform operations including specifying parameters associated with the radioports, the specifying operation specifying a constant channel capacity constraint, and computing composite powers for the radioport architectures in response to the parameters. Cost structures are determined in response to the composite powers for the radioport architectures, the cost structures being determined in response to the constant channel capacity constraint. The cost structures of the radioport architectures are compared to choose a least-cost one of the radioport architectures to be the one radioport architecture.
The above and other advantages of the present invention are carried out in yet another form by a computer-based method for selecting one of a plurality of radioport architectures of radioports in a wireless communication network. The method calls for specifying parameters associated with the radioports, the specifying operation specifying a constant offered load constraint, and identifying sizes of coverage areas of the radioports. The method further calls for ascertaining a quantity of radioports to support wireless communication in a total service area of the wireless communication network in response to the sizes of the coverage areas. Composite powers are computed for the radioport architectures in response to the parameters and cost structures are determined in response to the composite powers for the radioport architectures, the cost structures being determined in response to the constant offered load constraint. The determining operation includes applying a cost model to determine costs of one of the radioports responsive to the sizes of the coverage areas and combining each of the costs with the quantity of the radioports to obtain the cost structures of each of the radioport architectures. The cost structures of the radioport architectures are compared to choose a least-cost one of the radioport architectures to be the one radioport architecture.